Sir Alex Ferguson is content with Manchester United's position at the top of the table, ahead of their FA Cup tie against Reading. Photograph: Carl Recine/Action Images

Sir Alex Ferguson has labelled Manchester United's 12-point lead over Manchester City at the top of the Premier League "sensational".

In his programme notes ahead of Monday evening's FA Cup fifth round tie with Reading, Ferguson wrote of the last round of league games nine days ago: "Once I knew City had lost [at Southampton, 3-1] we'd been gifted an enormous opportunity to push on.

"A nine-point lead was good but not sensational – the chance of a 12-point advantage was a different story, so I scrapped my plans to rest a fair number of players [for Everton] with Real Madrid in mind three days later. We had a strong side out and I think the players sensed the opening for them was there." Everton were beaten.

"What a great weekend for Manchester United fans," Ferguson added. "First up for celebration was defeat for our nearest rivals, followed by our 2-0 win over Everton at Old Trafford."